The primary justification for this proposal for the purchase of a diagnostic ultrasound unit is that an instrument is not available on an as needed basis for this group of investigators. The research projects use the baboon as a nonhuman primate model and a diagnostic ultrasound is essential to provide us with a non- invasive method by which we can evaluate, characterize and implement our research protocols. A nucleus of eight investigators will utilize the instrument to achieve the following objectives; a) assess normal and induced follicular development in cycling female baboons and obtain preimplantation embryos and uterine endometrium to evaluate normal and altered secretory patterns during implantation; b) assess follicular development and ovulation to obtain embryos from various segments of the oviduct and harvest hydrosalpinx fluid to purify and characterize oviduct specific macromolecules; c) test oxytocin antagonists for preventing preterm labor by measuring intrauterine pressure changes by placing a catheter within the amniotic fluid and monitoring uterine contractility in response to the antagonists and sample umbilical cord blood to assess transplacental transfer of the antagonists in response to contractions; d) develop a baboon model to study transplacental infection of the fetus by infecting the mother with the HIV-l virus and the effects of directly infecting the fetus in utero; e) measure fetal growth rates and develop nomograms to evaluate and characterize fetal development in utero; f) train veterinarians, clinicians and residents in the use of diagnostic ultrasound to diagnose pregnancy, fetal development and fetal anomalies in a well managed breeding colony. Purchase of this instrument will contribute significantly to research output and clinical teaching and enable us to utilize our baboon colony to its fullest potential.